Interlocking cushioning mechanism for supporting seat portion and backrest of chair in integral fashion

Abstract

An interlocking cushioning mechanism for supporting a seat portion and a backrest of a chair in an integrally movable fashion. This mechanism has a primary mounting member secured to an upright support for swivel movement about the vertical axis thereof, slots formed in a portion of the primary mounting member which is located near the upper end of the upright support; a subsidiary mounting member having one end extending upwardly toward the rear of the chair and the other end secured to the slots by means of a shaft; a resilient member such as a spring held between the shaft and the forward end of the primary mounting member so as to cause the shaft to move rearwardly within the slot; a seat portion mounting frame for carrying the seat portion; and a backrest frame secured to the rear of the subsidiary mounting member. The resilient member is mounted by means of a simple mounting structure and the resilient force of the resilient member is altered with a minimal effort.

What is claimed is: 
     
       1. An interlocking cushioning mechanism for supporting a seat portion and a backrest of a chair in an integrally movable fashion, comprising: an upright support;   a longitudinally extending primary mounting member having a forward end and an opposite end, said primary mounting member being secured at said opposite end to an upper end of said upright support for swivel movement about the vertical axis thereof, and said primary mounting member being forwardly inclined upwardly toward the front of said chair;   a slot formed in a portion of said primary mounting member which is located in the vicinity and forward of said upper end of said upright support to which said primary mounting member is secured for swivel movement about said upright support, the longitudinal axis of said slot extending parallel with the longitudinal axis of said primary mounting member;   a subsidiary mounting member having a rearward end located on the side of said upright support opposite to said forward end of said primary mounting member and a forward end secured to said slot by means of a shaft extending normal to the longitudinal axis of said slot, and the vertical axis of said upright support;   a resilient member positioned within the body of said primary mounting member and held under compression between said shaft and said forward end of said primary mounting member and acting to cause said shaft to move rearwardly within said slot, the direction of action of said resilient member being parallel to the longitudinal axis of said primary mounting member, and the degree of resilient force of said resilient member being adjustable;   a seat portion mounting frame disposed across said opposite forward end of said primary mounting member and said rearward end of said subsidiary mounting member for carrying a seat portion; and   a backrest frame secured to said rearward end of said subsidiary mounting member.